Semiconductor devices generally generate heat whenever a high power is applied to the semiconductor since each semiconductor device exhibits an ohmic resistance that burns some electrical power into heat. As is known a semiconductor device may be damaged by high temperatures, since for example the silicon will exhibit so-called thermal exhaustion symptoms, e.g., metallization of the silicon. Accordingly, the temperature of a semiconductor structure should not exceed a predefined limit to prevent such damage.
To limit the temperature of a semiconductor structure the current flow through the structure can be shut down in case a predefined temperature limit is exceeded. In conventional chips or integrated circuits the temperature is measured at the estimated hottest and at the estimated coldest spot. Besides evaluating the measured temperatures directly to prevent overheating the measured temperatures can be compared to get the temperature difference as a second clue of the actual thermal stress of the semiconductor structures comprised in chip or integrated circuit.
In operation there are some situations prone to cause overheating of a semiconductor, particularly when large currents flow through the semiconductor. In one example a controller for controlling power supply for an electric motor or another load may experience large currents, for example, upon powering-on, i.e., the so-called inrush current peak. Furthermore, large currents may occur in case of a short-cut at the load. As a conventional means for limiting the generation of heat within the semiconductor a current limiter can be used for limiting the current while at simultaneously monitoring the temperature of the semiconductor. In case the measured temperatures indicate an overheat situation the corresponding chip or at least the semiconductor structure comprised therein that caused the situation is switched off to prevent any damage until the chip has cooled down. Thereafter, i.e., as soon as the temperatures have dropped below a predefined threshold, the semiconductor may be put into normal operation again. So whenever the measured temperatures indicate an overheat situation, the semiconductor is switched off for cooling down until being put into normal operation again. In this way the chip or integrated circuit may be operated in cycles of a loop. However, in case of a load having inductive characteristics, the process of switching-off the current flow does not instantly cut off the current flow. As a consequence the semiconductor may be further heated, which may cause damages of the semiconductor structure.